[libunwind] [libunwind] Detect cycles of length 1 (PR #103476)

[Fangrui Song via cfe-commits]

MaskRay wrote:

> This happens with musl libc in __clone(), which has incorrect DWARF unwind information.

Can you elaborate this? How is it incorrect? (tools/add-cfi.x86_64.awk on `musl/src/thread/x86_64/clone.s`, I assume)

I guess this workaround does address your issue, but for the upstream we really need more principled fix, instead of adding a hack.

https://github.com/llvm/llvm-project/pull/103476